Forecast consumption conceptual question

Question

Experts,
I am trying to understand what advantage does I have by consuming the forecast?
lets say last week (w0) I have forecast of 10 pcs, this week (w1) I have a forecast of 10 pcs and next week (w2) i have 10 pc forecast. I have backward consumption of 30 days set.
case 1 : w1 i got a sales order of 10, so it consumes my forecast of 10 and when mrp run, i get 10 planned orders and i convert them to prod orders and satisfy the order.
case 2: if in w1 i got a sales order of 10 more, system will consume 10 forecast from w0 (backward consumption of 30 days) and when mrp is run, planned order for 10 is created in w1.
even if i dont have a forecast of 10 in the last week, mrp will create a planned order of 10 to satisfy my new sales order. so what advantage do i get by "consuming" the forecast?

Answer 1

925,
Consumption enhances production stability.
You create a forecast so that you can prepare your business for production, and to support the beginning of execution of the plan, optionally to be executed at the FGs level, but more importantly at the lower levels of the BOMs, right down to raw material purchases.  To use your example, you have a demand plan for 10/10/10.  MRP then creates a supply plan of 10/10/10, and a purchasing plan of 10/10/10.  The assumption is that you created this plan to support future sales orders that you expect will eventually be entered.
So, now, the demand plan and the supply plan and the purchasing plan are in place.  10/10/10.  All levels of the BOM. Purchase orders have been placed, subassemblies are being manufactured. Now, a sales order is entered for 10.  This is additional demand.  If you had no consumption, you would have a demand plan of, say, 10/20/10 (10/10/10 from the forecast, and 0/10/0 from the sales order).  New planned orders would be e created.  New purchase reqs for RMs. Disruption of the smooth running of your supply chain! Yet, you don't really need to build these new planned orders or purchase reqs, since you already accounted for them when you created your forecast!  
This is why there is consumption.  You can prepare a demand plan, and a supply plan, and a purchasing plan, and when it comes time to execute, the actual execution will remain very close to the original plan.  If your forecasting were to be perfect (it never really happens, but it is a goal), then the execution would be exactly the same as the plan.  Everyone is prepared, no disruption, no expedites, no overstock.  You can achieve the maximum profitability possible.
Best Regards,
DB49